Predatory potential and functional response of Coccinella undecimpunctata Linnaeus (Coleoptera: Coccinellidae) on Brevicoryne brassicae (Linnaeus) (Homoptera: Aphididae)

The determination of functional response provides the foundation to determine the efficiency of a natural enemy for its use against a specific crop pest. The results indicated that the number of prey eaten by 1(st), 2(nd), 3(rd) and 4(th) instars, male and female adults of C. undecimpunctata increased significantly with increasing prey density. Prey consumption increased with development of larvae, i.e. the 4(th) instar consumed more number of aphids at each prey density than the 3(rd), 2nd, and 1(st) instars. Female adults consumed more aphids than the male adults. All stages of C. undecimpunctata exhibit a Type II functional response curve (a curvilinear rise to plateau) as B. brassicae densities increase, and the curve predicted by Holling's disk equation did not differ significantly from the observed functional response curve. The attack rate was highest with the lowest handling time, when adult females fed on B. brasicae, followed by adult males and 4(th) instar larvae. However, further field experiments are needed to confirm its potential.